Disturbed by good friends cat care habits while pet sitting! :(

I have a close friend who moved to NYC about a year ago with two cats.

We have been to visit and the cats had typically seemed ok, but the large boy kitty was very ready to attack guests all of the time. 

I agreed to pet sit the two kitties while they are on vacation for two weeks.

I was a little taken aback when I was told they often leave the cats for a week with no sitter. 

They also told me the cats don't get wet food, just dry all of the time and I could just go twice over the 10 days! 

Of course being a super cat lady I decided to go every other day to check on the fur babies. During my first visit, I was pretty horrified by a few things. 

1-The liter box was filled with poop and pee and had less than two inches of filthy liter.

They had told me they had just cleaned this and I wouldn't need to change it (in ten days!!!) ***.

I cleaned and filled to box to over four inches of liter which I always assumed was standard for any kitty if not low. When I told my friend I was doing this he seemed annoyed. The poor cats didn't even have enough litter to cover the poop prior. 

2. The girl kitty is not fixed. She is also very very underweight which they say is the way she has always been. To me its a pretty big medical issue and I would be concerned if she were my cat being that boney. 

3. The apartment overheats and they have no AC and use just fans. I worry that the cats are getting overheated. I left a fan on for them today. 

4. Upon entering the big boy cat was meowing like crazy and very upset. I fed him and tried to play with him but he kept hissing. Toward the end of my visit he hissed and ran toward me and attacked my leg leaving me bleeding with five huge cuts and scratch marks!

5-The only food they get is dry, and it's the worst stuff out there-9 lives  

I'm concerned for the kitties, and also a little nervous about going back to cat sit this week after being attacked. 

I don't know how to approach these issues with a close friend without offending them. I don't know if the lack of cat care is due to financial difficulties or lack of knowledge. 

Also how do I deal with psycho cat when trying to finish cat sitting!? lol 

Calmly explain to them and educate them about good nutrition - wet food. It's probably due to ignorance. Start the conversation by going, "Oh hey, I came across these really informative articles about cat nutrition when I was looking for info for my cat" so it's not like you were intentionally blaming her. Like a "I came across this and wanted to share" attitude would be best with a friend. If they aren't receptive, unfortunately there's nothing you can do. Some people are just set in their ways and beliefs and won't budge for anyone. Maybe try to sneak some cat gifts (of wet food cans) to your friend and say "Oh I had extra, here give these to your cats!" so at least they get some wet food in their diet.

I know people like this too, and for a while, one of them was my boyfriend... it's so sad. The most I've been able to do is provide them good care while I'm with them, and if your friend seems annoyed by any aspect of cat ownership, that's when you can take your opportunity to jump and be like "hey, I found this thing! It could make your life easier in X, Y, and Z ways!" For example, if they ever bring up the smell or condition of the litter box, casually bring up how feeding a higher quality diet and a wet diet can decrease the amount and smelliness of poops, the smelliness of pee, and it can help the cats feel fuller so they eat less as a whole, so the cost could level out when they have to buy food less frequently.

I also bought a bulk pack of canned food for my cats, but I told my friend "I have a few flavours our cats aren't big on/can't eat too often... I can give them to you to try with your cats! If they like it, I got this pack of 48 cans for $25 at X store. That could feed your cats for over a month and it's better than just dry" or something like that. Money speaks pretty loud even if people are very financially stable. If you "stumble upon" coupons or discounts for mid- or higher grade foods, share them and be like "this is a great deal!" In my friend's case, it was initially ignorance, but now I think it's a sense of denial that she could be doing anything wrong after a lifetime of owning cats the way she and her parents always have... thus, stubbornness.

If you can freeze a water bottle or some other sort of ice brick, putting that in front of the fan can get some cool air circulating.

Maybe boy cat's just stressed and/or not great with unfamiliar people, so being without his owner and only having someone who's kind of like a stranger set him off. I don't have much advice in this sense, except treat lightly and maybe toss treats to keep him distracted while you do your thing. Good luck!